DESCRIPTION: (Applicant's Description) The present program grant application concerns the use of a synthetic peptide (802-2 peptide) in clinical trials and the further development of modifications of the peptide treatment. As such, the proposed research of all projects in this program involves extensive use of synthetic peptides and the success of the program depends on the availability of high quality peptide materials. In this regard, the peptide synthesis core will be vital in providing these synthetic materials for each of the projects. In addition, it is expected that the core leader's experience with the design, synthesis, and study of chemical modifications to improve peptide activity and stability will allow the core to serve as an interactive resource for translating hypotheses about peptide structure and function into potential therapeutic agents and experimental design for testing their effects on T cell function.